In a design of, for example, a network system linking many computers via a network, a system structure diagram is created using CAD. Furthermore, attempts are made to check consistency of the system structure diagram created using CAD with a certain degree of automation.
CAD in a conventional printed circuit board design judges whether connections are good or not as a check of connectability between pins based on properties of signals passing through the pins. Such a check of connectability between pins in a CAD design drawing (part of DRC [Design Rule Check]) checks whether connections are good or not by hard-coding the properties of signals passing therethrough (e.g., connections are not possible between output signal pins). That is, it is necessary to code a check program for every individual check target and create a program for checking every characteristic and condition of various signals of the respective pins.
This method works fast but has extreme difficulty in handling the following cases. First, there is a case where connectability between pins whose properties are not clearly defined at the time of creating a library data/processing program is checked, and second, there is a case where a component using a new technique appears and a connectability check is speedily extended using the properties of the technique and so on, and in such cases, a program incorporating logic for a new connectability check needs to be created.
A card design verification method and a card design verification system described in Patent Document 1 (Japanese Patent Laid-Open No. 2004-287585) shown below carry out not only consistency verification of pin attributes of a connector but also verification of electric connections before and after the connector in connection verification between cards. Here, connection verification is also made possible between cards based on information of a network list for every card type and information of connection between the cards. However, when new pin attributes and signal characteristics are introduced just as the conventional printed circuit board design CAD, a program needs to be modified or added so as to enable such introduction to be verified every time.